A Basic Understanding Of The Laboratory Microscope

A laboratory microscope is a window into an entirely different world; or more precisely, it is a window into a part of our world which would otherwise be invisible. By definition, it's not possible to see individual microorganisms with the naked eye. While microscopes have been around the 16th century, even predating Anton van Leeuwnhoek's discovery of 'wee animalcules', the modern compound laboratory or medical microscope lets us view things on a microscopic level in a way which goes far beyond what the Dutch lens makers of the 1500s could have even imagined.

Most modern varieties of laboratory microscope are of the compound style, using an objective lens to magnify the specimen being viewed. The image is then projected to the ocular lens, which provides additional magnification.

The microscopes used in research laboratories and in clinical settings may be either optical microscopes using standard light, phase contrast, bright field or dark field illumination technologies; or they may be electron microscopes. The most frequently used type of laboratory or medical microscope is the bright field optical compound microscope, using dual lenses, a focusing apparatus and a source of light.

There are at least three and often more different objective lenses on the average laboratory microscope. The user may switch between the objectives as needed by rotating a piece on which the lenses are mounted, depending on the degree of magnification desired.
The usual arrangement of these lenses includes a low power objective; this objective is the shortest of the three and provides 10x magnification. The objective in the middle usually provides 40x magnification. The longest of the three objectives on most models of optical laboratory or medical microscope may provide 60x magnification or 100x magnification (100x objectives are typically oil-immersion lenses).

The magnification provided by a laboratory microscope is actually not the figures denoted by the magnification of the objective lenses, but these amounts multiplied by the power of the ocular lens, which is usually 10x. However, there is only so much that can be done with a standard light illuminated optical microscope. At a certain point, the resolution of the image begins to decline and may be of little to no use to the operator - the best resolution which most models of optical medical microscope can offer is around .2 micrometers; if greater resolution is required, other types of microscopy will be necessary.

The digital laboratory microscope is a newer development which has opened up new possibilities for optical microscopy. These instruments can transmit the images they capture to a monitor for easier viewing by several persons at once, making them a good choice for collaborative work and as an educational tool.

Additionally, the digital image data produced by the latest generations of microscope can be sent to a connected computer in the laboratory for further analysis, logging and future reference. A digital medical microscope can often save a considerable amount of time for users and making the images obtained even more useful for diagnostic purposes. The laboratory microscope has come a long way over the last four centuries and it's certain that we'd be just as astonished to see what the future holds as van Leeuwenhoek would be by the optical technologies in use today.